Hi Doganjo - The willow I have bought and being advised to use as a complete beginner is called buff willow. It has had its outer bark removed and dried. I am told it is easier to work with to begin with when you have to concentrate on technique and tightness of weave. At my last class we were given some green willow to work into the bottoms we were weaving and I found I could not keep the weave as tight and it was more slippery to work with, however I did like the contrast in colour so hopefully with practice I will be able to incorporate it. You use different lengths of willow for different weaves on the basket to gain the required thickness. At class we are handed what is required so I think it is going to be a challenge for me to choose from my own bundles.
I have also made a wigwam for the garden, this was made from dogwood 'stakes' and then woven with hurdle willow. We were looking at a book at the last class recommending materials you can weave with from the hedgerow so I am sure you would be able to use some of your willow, if you are interested in the name of the book I will try to find out for you. I have bought a book called Willow Work bu Mary Butcher and that looks like it is going to have good advice it. I do urge you to have a go at basket making, I am really enjoying it,